PrunesPrunes, which are dried plums, are commonly associated with digestive health, but they “have a magical power in terms of bone,” says Shirin Hooshmand, a San Diego State University assistant professor whose extensive research in animals and humans shows that eating the fruit can reverse and prevent bone loss. According to her latest, yet-to-be-published study, all it takes is five or six medium prunes a day to get this bone-preserving effect.